The present invention is directed to methods and devices for filtering fluid flow through body structures. Such devices are used in various parts of the body, such as the vascular system, to filter out unwanted material.
Filters are used in the vascular system to remove plaque and other material which can obstruct blood vessels. Vascular filtering devices may be used during other procedures such angioplasty, stenting, endarterectomy or atherectomy. During such interventional procedures, there is a danger of breaking plaque free from the vessel walls. Filters are used to prevent plaque and other material which may be dislodged during such interventional procedures from traveling downstream where they can obstruct or restrict blood flow.
A filtering device is disclosed in WO 98/33443 which published Aug. 6, 1998 by inventor Jay Yadav which is hereby incorporated by reference. One of the filters disclosed in the published application at FIG. 9 shows a filter which is expanded with a single spiral structural wire attached to the filter. A fiber is attached to the spiral wire and tension is applied by the fiber to collapse the spiral wire. When tension on the fiber is released, the wire and attached filter expand.
The present invention is directed to improved methods and devices for filtering fluid flow in patients and, in particular, for filtering blood flow.